There has been known a recording device that forms an image by ejecting droplets, such as ink, from a nozzle. In the recording device, a multipath system is known, in which a recording head including a nozzle for ejecting ink is moved in a reciprocating manner in a main-scanning direction relative to a recording medium and the recording medium is relatively moved in a sub-scanning direction to form an image.
However, in the multipath system, the recording head repeatedly scans the same area on the recording medium, so that a recording speed decreases. To improve the productivity, it is necessary to reduce the number of scans; however, image degradation is increased with a decrease in the number of scans. As a technology for suppressing image degradation, for example, a technology is disclosed in which a print mask with different arrays of mask values for determining ejection or non-ejection of ink is adjusted to each of blocks that are obtained by dividing a plurality of nozzles disposed on a recording head, and print data is generated by using the mask values.